Printed materials, such as books for example, are typically produced in multiple quantities for efficiency reasons. Generally, the cost to produce a book can be reduced by printing multiple copies of the book during the same printing run. Printing multiple copies of a book takes advantage of the efficiencies of quantities of scale and spreads fixed costs, such as setup costs, over multiple quantities of the book rather than applying those costs to a single copy of the book or relatively few copies. As multiple quantities of a book are produced, the books may be stacked together at some point in the manufacturing line prior to being individually bound. An efficient and cost effective way of determining where any one particular book in the stack begins and ends would be quite useful to separate each individual, unbound book from the stack of books.